Permanent magnet pulley



Dec. 13, 1966 A. PALM PERMANENT MAGNET PULLEY Filed Aug. 24, 1964 INVENTOR. HERA/HARD A. PALM ATT United States Patent C).

3,292,126 PERMANENT MAGNET PULLEY Bernhard A. Palm, Los Angeles, Calif, assignor to Buck Manufacturing Company, Los Angeles, Callfi, a corporation of Delaware Filed Aug. 24, 1964, Ser. No. 391,464 2 Claims. (Cl. 335302) This invention relates to permanent magnet pulleys in general. More particularly, this invention relates to a permanent magnet pulley constructed to reduce the magnetic flux threading through the interior of the pulley where no work is to be performed.

An object of this invention is to provide an improved permanent magnet pulley constructed to increase the magnetic field of the outside of the pulley for a given size or number of permanent magnets employed therein.

Another object of this invention is to provide an improved permanent pulley with magnetic pole rings therein clamped to rows or stacks of permanent magnet blocks thereof shaped to guide the magnetic flux set up by the blocks to the exterior of the pulley where useful work is to be performed thereby.

Still another object of this invention is to provide an improved permanent magnet pulley in which the permanent magnets are arranged against the inside surface of the pulley shell and in which the permanent magnets are provided with magnetic pole rings, the radial and axial dimensions of which are proportioned so that a greater percentage of the magnetic flux of the permanent magnets is caused to thread through the shell to the exterior thereof where useful work is to 'be performed thereby.

Other and further objects of this invention will be apparent to those skilled in the art to which it relates from the following specification, claims and drawing, in which briefly:

FIG. 1 is a sectional view taken across a pulley constructed in accordance with this invention and this sectional view is taken along the line 1-1 of FIG. 2; and

FIG. 2 is a longitudinal view of a permanent pulley constructed in accordance with this invention in which the said pulley is shown partially in section taken along the line 22 of FIG. 1.

Referring to the drawing in detail, reference numeral designates a hollow tubular pulley shell of non-magnetic material which is supported on the shaft 13 by discs 11, one of which is shown in FIG. 2, and another of which (not shown) is positioned in the right-hand end portion of the shell 10. The disc 11 is held on the shaft 13 by the collar 12, which may .be attached to the shaft in any conventional manner. The shell 10 houses a plurality of magnetic pole rings, such as the rings 15, 16 and 17, between which rows of magnetic blocks extending parallel to the shaft 13 are positioned. The rows of magnetic blocks positioned between rings and 16 consist of individual magnetic blocks 14 each of which is a permanent magnet. These permanent magnetic blocks 14 are arranged in parallel rows with only the corners 14a of the blocks in adjacent rows close to each other or actually touching when the magnetic pole rings 15 and 1 6 clamp the magnetic blocks together. The rings 15 and 16 function .as the pole pieces for the magnetic block rows or stacks in which the magnetic blocks 14 are arranged so that the magnetic elfect thereof is cumulative, whereby one of the rings 15-16 functions as a south magnetic pole, and the other functions as a north magnetic pole by virtue of the total magnetic field set up by the blocks 14 in all of the stacks or rows between the rings.

The sides of the magnetic blocks 14 engaging the in- 3,292,126 Patented Dec. 13, 1966 ice ner surface of the shell 10 may be of arcuate configuration corresponding to the curved inner surface of this shell so that these sides of the blocks are flush against the inner surface of the shell. This may not be important where narrow individual blocks are used. However, if wide *blocks are used a relatively large air gap configuration in these magnetic pole rings facilitating the maximum utilization of the magnetic field set up by the permanent magnet blocks 14 on the outside periphery of the shell 10 where the magnetic field is utilized for doing work. This accomplished by providing magnetic pole rings 15 and 16 of sufiicient thickness in the axial direction so as to provide a low reluctance path therethrough from the end blocks of the stacks of magnetic blocks toward the inner surfaces of the shell 10 so that these magnetic rings guide the magnetic field outward toward the work-producing area on the outside of the shell. At the same time, the magnetic rings 15 and 16, by not extending over the inner portion of the outside surfaces of the end blocks 14, tend to minimize the magnetic field, leaving these surfaces of the blocks and extending into the shell toward the shaft 13 where no useful Work is to be performed.

Additional magnetic block units may be provided in the shell 10, as desired; thus, an additional pole ring 17 may be provided in the shell 10, either abutting magnetic pole ring 16 or spaced therefrom, and additional magnetic blocks 18 may be held in position in the shell by the ring 17 and an additional ring such as the pole ring 15 positioned in the right-hand part of the shell (not shown). The number of such magnetic block units positioned in the shell 10 is determined by the length of this shell, and these magnetic block units and pole rings are held assembled in the shell by end plates such as the plate 11, which are positioned one at each end of the shell. These end plates are attached to the interior of the shell 10 by welding, brazing or the like, and they are held on the shaft 13 by means of retaining collars such as the collar 12.

While I have shown a preferred embodiment of the invention, it will be understood that the invention is capable of variation and modification from the form shown so that its scope should be limited only by the scope of the claims appended hereto.

What I claim is:

1. A permanent magnet pulley comprising a hollow shell of non-magnetic material, means for supporting said shell on a shaft, permanent magnet means positioned in said shell engaging the inner surface of said shell, said magnet means having a radial width extending inside of said shell a predetermined distance toward said shaft, magnetic pole rings fitted into said shell, said pole rings engaging only parts of the ends of said permanent magnet means adjacent to said shell and extending inward from the inner surface of said shell a distance substantially less than the radial width of said permanent magnet means so that substantial areas of the ends of said magnet means are exposed to the air, said magnetic pole rings having a cross-sectional area that is large enough to provide a low reluctance path for the magnetic flux from the ends of said permanent magnet means to guide the magnetic flux from the ends of said magnet means outward through said shell to the outside of the pulley where useful work is to be performed and magnetic flux tending to thread through the air gap inside of the pulley from said in- 3 nermost areas of the ends of said magnet means is reduced.

2. A permanent magnet pulley comprising a hollow cylindrical shell of non-magnetic material, means supporting said shell on a shaft extending along the axis of said shell, permanent magnet means in said shell forming a hollow magnet structure with one magnetic pole at one end and the other magnetic pole at the other end, said hollow magnetic structure comprising a plurality of permanent magnets stacked against each other on radii of said shell so that the outer ends of said magnets are adjacent the inside sunface of said shell and ring members engaging the ends of said magnet stacks forming the said magnetic poles, the outer peripheral surfaces of said ring members being adjacent to the 1 inside surface of said shell, the widths of said ring members in the directions of said radii being substantially 5 the Working surface around the circumference of the magnet pulley.

References Cited by the Examiner UNITED STATES PATENTS 7/ 1961 Buss et a1 20921-9 2,992,736 7/ 1961 Buss et a1 209--2 23 3,146,191 8/ 196 4 Greenwald 317201 X BERNARD A. GILHEANY, Primary Examiner. o

G. HARRIS, Assistant Examiner. 

1. A PERMANET MAGNET PULLEY COMPRISING A HOLLOW SHELL OF NON-MAGNETIC MATERIAL, MEANS FOR SUPPORTING SAID SHELL ON A SHAFT, PERMANENT MAGNET MEANS POSITIONED IN SAID SHELL ENGAGING THE INNER SURFACE OF SAID SHELL, SAID MAGNET MEANS HAVING A RADIAL WIDTH EXTENDING INSIDE OF SAID SHELL A PREDETERMINED DISTANCE TOWARD SAID SHAFT, MAGNETIC POLE RINGS FITTED INTO SAID SHELL, SAID POLE RINGS ENGAGING ONLY PARTS OF THE ENDS OF SAID PARMANENT MAGNET MEANS ADJACENT TO SAID SHELL AND EXTENDING INWARD FROM THE INNER SURFACE OF SAID SHELL A DISTANCE SUBSTANTIALLY LESS THAN THE RADIAL WIDTH OF SAID PERMANENT MAGNET MEANS SO THAT SUBSTANTIAL AREAS OF THE ENDS OF SAID MAGNET MEANS ARE EXPOSED TO THE AIR, SAID MAGNETIC POLE RINGS HAVING A CROSS-SECTIONAL AREA THAT IS LARGE ENOUGH TO PROVIDE A LOW RELUCTANCE PATH FOR THE MAGNETIC FLUX FROM THE ENDS OF SAID PERMANENT MAGNET MEANS TO GUIDE THE MAGNETIC FLUX FROM THE ENDS OF SAID MAGNET MEANS OUTWARD THROUGH SAID SHELL TO THE OUTSIDE OF THE PULLEY WHERE USEFUL WORK IS TO BE PERFORMED AND MAGNETIC FLUX TENDING TO THREAD THROUGH THE AIR GAP INSIDE OF THE PULLEY FROM SAID INNERMOST AREAS OF THE ENDS OF SAID MAGNET MEANS IS REDUCED. 